JP5722460B2 - Acrylic acid (salt) -maleic acid (salt) copolymer composition, method for producing the same, and detergent composition - Google Patents

Description

The present invention relates to an acrylic acid (salt) -maleic acid (salt) copolymer composition, a method for producing the same, and a detergent composition.

Acrylic acid (salt) -maleic acid (salt) based copolymers are conventionally known to exhibit excellent chelating and dispersing actions, such as detergent builders, scale inhibitors, inorganic pigment dispersants and the like. It is used in a wide range of applications (see, for example, Patent Documents 1 to 3). Patent Document 4 discloses an acrylic acid (salt) -maleic acid (salt) copolymer having a clay dispersibility in high-hardness water of 50% or more and a calcium ion scavenging capacity of 270 mgCaCO ³ / g or more. Coalescence is disclosed. Further, in Patent Document 4, since the copolymer has a high ability to disperse clay in high-hardness water and also has a high calcium ion scavenging ability, a detergent composition using the copolymer has a high composition in the United States, China, and the like. It is disclosed that it exhibits excellent cleaning ability even in areas of hardness water.

Japanese Patent No. 2574144 JP-A 63-235313 JP 58-67706 A JP 2000-53729 A

In general, it is known that when clothes are repeatedly washed with water having high hardness, the clothes become soiled (yellowish) due to the deposition of calcium on the clothes. On the other hand, with the recent increase in consumers' awareness of environmental problems, consumers are trying to save water by using the remaining hot water in the bath for washing. Increasing the hardness of washing water due to concentration of ingredients has become a problem. Therefore, the components added to the detergent (for example, polymers) are insolubilized in the ability to capture calcium in washing water (calcium capturing ability) and in high-hardness washing water in order to suppress deposition on clothing. Physical properties such as difficult performance (gel resistance) are required. Although various polymers have been reported as described above, at present, no polymer has been developed that has extremely good calcium scavenging ability and gel resistance.

The present invention has been made in view of the above situation, and has an acrylic acid (salt) -maleic acid (salt) copolymer composition and a detergent composition, which have extremely good calcium scavenging ability and gel resistance. The purpose is to provide goods. Another object of the present invention is to provide a production method capable of suitably obtaining an acrylic acid (salt) -maleic acid (salt) copolymer composition having such excellent physical properties.

The inventors of the present invention have made extensive studies on a polymer and its composition capable of exhibiting a good calcium scavenging ability and gel resistance. As a result, the weight average molecular weight is in a predetermined range and a structure derived from acrylic acid (salt). An acrylic acid (salt) -maleic acid (salt) copolymer containing a unit and a structural unit derived from maleic acid (salt) in a specific molar ratio, and a specific sulfur atom-containing low molecular weight compound, and When the content of the sulfur atom-containing low molecular weight compound is within a predetermined range, it can exhibit extremely good calcium scavenging ability and gel resistance, and is suitable for various uses such as a detergent composition. I found it to be a thing. Further, when such a copolymer composition is obtained, a monomer component containing acrylic acid (salt) and maleic acid (salt) is polymerized in the presence of persulfuric acid (salt) and bisulfite (salt). The present inventors have found that the use of a production method including a step for producing a copolymer composition having excellent physical properties can be suitably obtained. Furthermore, it discovered that the detergent composition containing said acrylic acid (salt) -maleic acid (salt) type | system | group copolymer and a specific sulfur atom containing low molecular weight compound had the outstanding cleaning ability. And, it is found that these copolymer compositions and detergent compositions can exhibit excellent cleaning ability even in extremely hard water areas such as the United States, China, Europe, etc., and solve the above problems brilliantly. The present invention was reached.

That is, the present invention is a copolymer composition comprising an acrylic acid (salt) -maleic acid (salt) copolymer and a sulfur atom-containing low molecular weight compound, and the copolymer has the following general formula ( 1) and the structural unit (II) represented by the following general formula (2), the molar ratio of the structural unit (I) to the structural unit (II) ( The structural unit (I) / structural unit (II)) is 80/20 to 95/5, the weight average molecular weight of the copolymer is 2000 or more and 10,000 or less, and the sulfur atom-containing low molecular compound is , 3-sulfopropionic acid (salt), and the content of 3-sulfopropionic acid (salt) is 0.01 to 10% by mass with respect to 100% by mass of the total solid content of the copolymer composition. An acrylic acid (salt) -maleic acid (salt) copolymer composition.

In formula (1), M represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group.

In formula (2), M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group or an organic amine group.

The present invention is also a method for producing the acrylic acid (salt) -maleic acid (salt) copolymer composition, wherein the production method comprises the presence of persulfuric acid (salt) and bisulfurous acid (salt). And a method for producing an acrylic acid (salt) -maleic acid (salt) copolymer composition including a step of polymerizing a monomer component containing acrylic acid (salt) and maleic acid (salt).

The present invention is also a detergent composition comprising the acrylic acid (salt) -maleic acid (salt) copolymer composition.

The present invention is also a detergent composition comprising an acrylic acid (salt) -maleic acid (salt) copolymer and a sulfur atom-containing low molecular weight compound, the copolymer comprising the above general formula (1) The structural unit (I) represented by the formula (2) and the structural unit (II) represented by the general formula (2), and the molar ratio of the structural unit (I) to the structural unit (II) (structural unit (I) / structural unit (II)) is 80/20 to 95/5, the weight average molecular weight of the copolymer is 2000 or more and 10,000 or less, and the sulfur atom-containing low molecular compound is 3 -Detergent composition containing sulfopropionic acid (salt), wherein the content of 3-sulfopropionic acid (salt) is 0.0005 to 2% by mass with respect to 100% by mass of the total solid content of the detergent composition But there is.
The present invention is described in detail below. In addition, the form which combined each preferable form of this invention described below 2 or 3 or more is also a preferable form of this invention.

[Acrylic acid (salt) -maleic acid (salt) copolymer composition]
The acrylic acid (salt) -maleic acid (salt) copolymer composition (hereinafter also referred to as “copolymer composition”) of the present invention is an acrylic acid (salt) -maleic acid (salt) copolymer. And a sulfur atom-containing low molecular weight compound, each of these containing components can be used alone or in combination of two or more. Further, if necessary, one or more other components may be further contained.

The acrylic acid (salt) -maleic acid (salt) copolymer (hereinafter also referred to as “copolymer”) includes the structural unit (I) represented by the general formula (1) and the general formula ( And at least the structural unit (II) represented by 2).

In the above general formulas (1) and (2), M, M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group or an organic amine group. Examples thereof include alkali metal atoms such as atoms, sodium atoms and potassium atoms; alkaline earth metal atoms such as calcium atoms and magnesium atoms; transition metal atoms such as iron; Among these, an alkali metal atom or an alkaline earth metal atom is suitable, more preferably an alkali metal atom, and still more preferably a sodium atom or a potassium atom. The organic amine group is a structural portion derived from a primary to quaternary amine in a structure in which a primary to quaternary amine has neutralized a carboxyl group, such as methylamine and ethylamine. , Groups derived from alkylamines such as diethylamine and triethylamine; groups derived from alkanolamines such as monoethanolamine and diethanolamine; groups derived from polyamines such as diethyleneamine and diethylenetriamine;
In the general formula (1), M is an ammonium group refers to a structure represented by —CH ₂ CH (COONH ₄ ) —.

M, M ¹ and M ² in the general formulas (1) and (2) are the same or different and are preferably a hydrogen atom, a sodium atom or a potassium atom. Thereby, when the said copolymer and copolymer composition are used for detergent use etc., the improvement effect of a cleaning power, etc. are expressed further.

The structural unit (I) represented by the general formula (1) is also referred to as a structural unit derived from acrylic acid (salt). Acrylic acid (salt) means acrylic acid and / or acrylate.
“Containing a structural unit derived from acrylic acid (salt)” means that the finally obtained copolymer contains the structural unit (I), and polymerizing acrylic acid (salt). It is not restricted only to what was introduce | transduced in the copolymer by.
The structural unit (I) is preferably formed by polymerizing a monomer component containing acrylic acid (salt) in the presence of a polymerization initiator.

The structural unit (II) represented by the general formula (2) is also referred to as a structural unit derived from maleic acid (salt). The maleic acid (salt) means maleic acid and / or maleate (including a form in which both carboxyl groups are carboxyl groups and a form in which only one carboxyl group is a salt). .
In addition, “including a structural unit derived from maleic acid (salt)” means that the finally obtained copolymer includes the structural unit (II), and polymerizing maleic acid (salt). It is not restricted only to what was introduce | transduced in the copolymer by.
The structural unit (II) is preferably formed by polymerizing a monomer component containing maleic acid (salt) in the presence of a polymerization initiator.

In the present specification, a salt (for example, a salt in an acrylate salt or a maleate salt) means a metal salt, an ammonium salt, or an organic amine salt. Examples of the metal salt include alkali metal salts such as lithium salt, sodium salt and potassium salt; alkaline earth metal salts such as calcium salt and magnesium salt; transition metal salts such as iron salt; Examples of organic amine salts include alkylamine salts such as methylamine salts, ethylamine salts, diethylamine salts, and triethylamine salts; alkanolamine salts such as monoethanolamine salts and diethanolamine salts; polyamines such as diethyleneamine salts and diethylenetriamine salts. Salt; and the like. Among these salts, alkali metal salts or alkaline earth metal salts are preferable. An alkali metal salt is more preferable, and a sodium salt or potassium salt is still more preferable.

In the copolymer, the molar ratio of the structural unit (I) represented by the general formula (1) and the structural unit (II) represented by the general formula (2) (structural unit (I) / The structural unit (II)) is 80/20 to 95/5. That is, the copolymer contains the structural unit (I) and the structural unit (II) in a molar ratio (structural unit (I) / structural unit (II)) = 80/20 to 95/5. When the molar ratio is within this range, the calcium capturing ability and gel resistance of the copolymer and the copolymer composition are sufficient. The molar ratio is preferably 82/18 to 92/8, more preferably 85/15 to 90/10.

In addition to the structural units (I) and (II) described above, the copolymer also includes one or more structural units derived from other monomers (also referred to as “structural unit (III)”). Further, it may be included. The structural unit (III) derived from other monomer is a structural unit derived from a monomer other than acrylic acid (salt) and maleic acid (salt) (this is referred to as “other monomer”). Means.
Here, “including a structural unit derived from another monomer” means that the finally obtained copolymer includes a structural unit (III) derived from another monomer. Further, it is not limited to those introduced into the copolymer by polymerizing other monomers.
The structural unit (III) is preferably formed by polymerizing monomer components including other monomers in the presence of a polymerization initiator.
When the structural unit (III) is a structural unit derived from, for example, methyl acrylate, the structural unit can be represented by “—CH ₂ —CH (COOCH ₃ ) —”. That is, a structural unit derived from another monomer is a structure in which a polymerizable double bond of another monomer is opened (double bond (C═C) is a single bond (—C—C— )).

The other monomers are not particularly limited. For example, unsaturated monocarboxylic acid monomers other than acrylic acid (salt) such as methacrylic acid, crotonic acid, and salts thereof; fumaric acid, itaconic acid , Citraconic acid, and salts thereof, and other unsaturated dicarboxylic acid monomers other than maleic acid (salt); amide monomers such as (meth) acrylamide and t-butyl (meth) acrylamide; (meth) Hydrophobic monomers such as acrylic ester, styrene, 2-methylstyrene, vinyl acetate; vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3 -Allyloxy-2-hydroxypropanesulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, 2- Unsaturated sulfonic acid monomers such as droxysulfopropyl (meth) acrylate, sulfoethylmaleimide and salts thereof; 3-methyl-2-buten-1-ol (prenol), 3-methyl-3-butene -1-ol (isoprenol), 2-methyl-3-buten-2-ol (isoprene alcohol), 2-hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene Glycol monoisoprenol ether, polypropylene glycol monoisoprenol ether, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, glycerol monoallyl ether, α-hydroxyacrylic acid, N- Hydroxyl-containing unsaturated monomers such as methylol (meth) acrylamide, glycerol mono (meth) acrylate, vinyl alcohol; cationic monomers such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide; ) Nitrile monomers such as acrylonitrile; phosphorus-containing monomers such as (meth) acrylamide methanephosphonic acid, (meth) acrylamide methanephosphonic acid methyl ester, 2- (meth) acrylamide-2-methylpropanephosphonic acid; etc. Is mentioned. These monomers may use only 1 type and may use 2 or more types together.

In the copolymer, the content molar ratio of the total of the structural units (I) and (II) and the structural units derived from the other monomer (III) (the structural unit (I) and the structural unit (II ) And the structural unit (III)) is preferably 100/0 to 80/20. That is, when the total amount of the structural units (I), (II) and (III) is 100 mol%, the structural unit (III) is preferably 20 mol% or less. Within this range, the calcium scavenging ability and gel resistance of the copolymer and copolymer composition can be further improved. The molar ratio is more preferably 100/0 to 85/15, still more preferably 100/0 to 90/10.

It is also preferable that the copolymer has (includes) a sulfonic acid (salt) group at at least one main chain terminal. As a result, the calcium capturing ability and gel resistance of the copolymer and the copolymer composition are further improved, and the effect of the present invention that can exhibit excellent detergency even in areas of high hardness water is further exhibited. It becomes possible to do.
The fact that the copolymer has a sulfonic acid (salt) group at at least one main chain terminal can be confirmed by, for example, ¹ HNMR analysis.

The sulfonic acid (salt) group means a sulfonic acid group and / or a sulfonic acid group. For example, “—SO ₃ M” (M represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group. Preferred examples of the metal atom and the organic amine group are as described above.

The sulfonic acid (salt) group at the end of the main chain can be introduced into the copolymer molecule by polymerizing the monomer component in the presence of bisulfurous acid (salt), as will be described later. . That is, the copolymer is preferably obtained by polymerizing a monomer component in the presence of bisulfurous acid (salt), whereby a part of bisulfurous acid (salt) acts as a chain transfer agent, A sulfonic acid group (—SO ₃ M) is incorporated at the end of the main chain of the copolymer molecule. Bisulfite (salt) means bisulfite and / or a salt thereof.
The sulfonic acid (salt) group at the end of the main chain is also referred to as a structural unit derived from bisulfite (salt).

The copolymer has a weight average molecular weight (also referred to as Mw) of 2000 or more and 10,000 or less. When the weight average molecular weight is in the range of 2000 to 10,000, the copolymer and the copolymer composition can exhibit good calcium deposition preventing ability. The lower limit of the weight average molecular weight is preferably 2500 or more, more preferably 3000 or more, and the upper limit is preferably 9000 or less, more preferably 8000 or less.

The copolymer preferably has a dispersity (a value obtained by weight average molecular weight Mw / number average molecular weight Mn, also referred to as molecular weight distribution) of 1.5 to 10. Thereby, the ability to prevent calcium deposition can be further improved. More preferably, it is 1.5-5.0, More preferably, it is 1.5-2.7.
In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by the methods described in Examples described later.

In the copolymer composition, the content of the copolymer is preferably 1 to 99% by mass with respect to 100% by mass of the copolymer composition, for example.

The copolymer composition also contains a sulfur atom-containing low molecular compound in addition to the above-described copolymer. The sulfur atom-containing low molecular weight compound contains 3-sulfopropionic acid and / or a salt thereof (referred to as “3-sulfopropionic acid (salt)”).
Content of the said 3-sulfopropionic acid (salt) is 0.01-10 mass% with respect to 100 mass% of solid content total amount of the said copolymer composition (however, Na salt type conversion). By being in this range, the calcium scavenging ability and gel resistance of the copolymer composition can be enhanced. The upper limit of the content of 3-sulfopropionic acid (salt) (in terms of Na salt type) is preferably 9.5% by mass or less, more preferably 9% by mass or less, and still more preferably 8.5% by mass or less. . The lower limit of the content of 3-sulfopropionic acid (salt) (Na salt type conversion) is not particularly limited, but is preferably 0.1% by mass or more, more preferably 1% by mass or more, More preferably, it is 1.5 mass% or more, Most preferably, it is 2 mass% or more, Most preferably, it is 2.5 mass% or more.
In this specification, “Na salt type conversion” means calculating a mass ratio with an object as a sodium salt (Na salt). For example, 3-sulfopropionic acid (salt) is 3-sulfopropion. Calculate mass percentage as sodium acid.
In the present specification, “solid content” means all components except volatile components, in other words, non-volatile components.

The sulfur atom-containing low molecular weight compound preferably also contains 2-sulfosuccinic acid and / or a salt thereof (referred to as “2-sulfosuccinic acid (salt)”).
The content of the 2-sulfosuccinic acid (salt) is preferably 0.01 to 4% by mass in terms of Na salt type with respect to 100% by mass of the total solid content of the copolymer composition. Thereby, the calcium capture | acquisition ability and gel resistance by the said copolymer composition can be improved further. The upper limit (in terms of Na salt type) of the content of the 2-sulfosuccinic acid (salt) is preferably 3.5% by mass or less. Although the lower limit (Na salt type conversion) of content of the said 2-sulfosuccinic acid (salt) is not specifically limited, For example, 1 mass% or more is preferable.

The sulfur atom-containing low molecular weight compound preferably also contains a sulfate.
It is preferable that the content of the sulfate is 0.01 to 5% by mass in terms of Na salt type with respect to 100% by mass of the total solid content of the copolymer composition. Thereby, the calcium capture | acquisition ability and gel resistance by the said copolymer composition can be improved further. Preferably it is 4.5 mass% or less as an upper limit of content of the said sulfate, More preferably, it is 4 mass% or less. The lower limit of the sulfate content is not particularly limited, but is preferably 1% by mass or more, for example.

The copolymer composition may also contain residual monomers, other residual raw materials, by-products other than the components described above, and the like.
When a residual monomer is contained in the copolymer composition, the content of the residual monomer is preferably, for example, 0 to 1000 ppm with respect to the total solid content of the copolymer composition. It is. More preferably, it is 500 ppm or less.
In addition, it is preferable to reduce other residual raw materials and by-products other than the above-described components as much as possible unless otherwise mentioned.

The copolymer composition may further contain a solvent such as water (also referred to as a solvent). When a solvent is included, a solvent containing water is preferable. More preferred is water.
The content of the solvent in the copolymer composition is preferably 0 to 99% by mass with respect to 100% by mass of the copolymer composition.

[Method for Producing Acrylic Acid (Salt) -Maleic Acid (Salt) Copolymer Composition]
The copolymer composition of the present invention includes a step of polymerizing a monomer component containing acrylic acid (salt) and maleic acid (salt) in the presence of persulfuric acid (salt) and bisulfurous acid (salt). It can be obtained by a manufacturing method. Such a manufacturing method is also one aspect of the present invention. By carrying out the polymerization reaction in combination with persulfuric acid (salt) and bisulfurous acid (salt), it is possible to suitably obtain the above copolymer composition that is extremely excellent in calcium capturing ability and gel resistance.

<Monomer composition>
In the monomer component, the use ratio of acrylic acid (salt) and maleic acid (salt) is 80/20 to 95/5 in molar ratio (acrylic acid (salt) / maleic acid (salt)). Is preferred. By setting it within this range, the calcium capturing ability and gel resistance of the copolymer and the copolymer composition can be increased, and the polymerization reaction can be performed at a high polymerization rate. It becomes possible to obtain the said copolymer and copolymer composition. More preferably, it is 82 / 18-92 / 8, More preferably, it is 85 / 15-90 / 10.

In addition to acrylic acid (salt) and maleic acid (salt), the monomer component further includes one or more other monomers that can be copolymerized with either or both of them. It may be. Other monomers are as described above.
In the above monomer component, the ratio of the total amount of acrylic acid (salt) and maleic acid (salt) to the amount of other monomers used is the molar ratio (acrylic acid (salt) and maleic acid (salt). )) / Total amount of other monomers) is preferably 100/0 to 80/20. By setting it as this range, the calcium capturing ability and gel resistance by the said copolymer and copolymer composition can be improved more. More preferably, it is 100 / 0-85 / 15, More preferably, it is 100 / 0-90 / 10.

<Persulfuric acid (salt) such as bisulfite (salt)>
The polymerization step of the monomer component is performed in the presence of persulfuric acid (salt) and bisulfurous acid (salt). The copolymer composition obtained by such a production method is preferably acrylic acid ( Salt) -maleic acid (salt) copolymer, a sulfur atom-containing low molecular compound derived from persulfuric acid (salt), and a sulfur atom-containing low molecular compound derived from bisulfurous acid (salt). .
In addition, as a sulfur atom containing low molecular weight compound derived from persulfuric acid (salt), sulfate is a main component, and as a sulfur atom containing low molecular weight compound derived from bisulfurous acid (salt), 3-sulfopropionic acid ( Salt) and 2-sulfosuccinic acid (salt) are the main components.
These sulfur atom-containing low molecular weight compounds are preferably contained in the copolymer composition in the above-described content ratio.

In the said polymerization process, persulfuric acid (salt) and bisulfurous acid (salt) can use 1 type (s) or 2 or more types, respectively.
The persulfuric acid (salt) mainly acts as a polymerization initiator. As the persulfuric acid (salt), for example, persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate are suitable. Moreover, you may use together 1 type, or 2 or more types of another polymerization initiator with persulfuric acid (salt). Examples of other polymerization initiators include hydrogen peroxide, azo compounds, and organic oxides.

The bisulfite (salt) acts mainly as a chain transfer agent. In addition to bisulfurous acid (salt), one or more other chain transfer agents may be used in combination.
As the bisulfite (salt), bisulfites such as sodium bisulfite, potassium bisulfite, and ammonium bisulfite are preferable.
In the present invention, in addition to the bisulfurous acid (salt) or in place of the bisulfurous acid (salt), one or more compounds capable of generating bisulfurous acid (salt) can be used. . Preferable examples of the compound capable of generating bisulfite (salt) include pyrosulfite (salt), dithionite (salt), and sulfurous acid (salt).
Among the compounds capable of generating bisulfite (salt) and bisulfite (salt), bisulfite (salt) is preferable.

In the above polymerization step, the use ratio of persulfuric acid (salt) and bisulfurous acid (salt) is 1 / 0.5 to 1/5 in mass ratio (persulfuric acid (salt) / bisulfurous acid (salt)). Is preferred. Within this range, an increase in the molecular weight of the copolymer can be further prevented, and the molecular weight distribution can be further narrowed. More preferably, it is 1/1 to 1/4.

Moreover, in the said polymerization process, the total usage-amount of persulfuric acid (salt) and bisulfurous acid (salt) shall be 5-20g with respect to 1 mol of all the monomer components used for the said polymerization process. preferable. Within this range, the increase in the molecular weight of the copolymer can be further prevented, the molecular weight distribution can be narrowed, and the generation of sulfur atom-containing low molecular weight compounds as impurities can be further prevented. In addition, the content ratio of the sulfur atom-containing low molecular weight compound in the obtained copolymer composition can be controlled by the above-described range. More preferably, it is 10-15g.

<Multivalent metal ion>
The polymerization step may also be performed in the presence of a polyvalent metal ion for the purpose of accelerating polymerization. 1 type (s) or 2 or more types can be used for a polyvalent metal ion.
As the polyvalent metal ions, for example, iron ions (Fe ²⁺ , Fe ³⁺ ), vanadium ions (V ²⁺ , V ³⁺ , VO ²⁺ ), copper ions (Cu ²⁺ ), and the like are preferable. It is preferable to use it.

The supply form of the polyvalent metal ions is not particularly limited. For example, the polyvalent metal ions can be present in the polymerization system by using a metal and / or metal compound that is ionized in the polymerization reaction system in the polymerization step. Is preferred. For example, it is preferable to add a solution (preferably an aqueous solution or an aqueous solution) obtained by dissolving such a metal and / or metal compound to the polymerization system.

Examples of the metal that is ionized in the polymerization reaction system include iron, vanadium, and copper.

Examples of the metal compound ionized in the polymerization reaction system include vanadium oxytrichloride, vanadium trichloride, vanadium oxalate, vanadium sulfate, vanadic anhydride, ammonium metavanadate, ammonium sulfate vanadium ((NH ₄ ) ₂ SO ₄ · VSO ₄ · 6H ₂ O), ammonium sulfate vanadas ((NH ₄ ) V (SO ₄ ) ₂ · 12H ₂ O), copper (II) acetate, copper (II) bromide, copper (II) acetyl acetate, Cupric chloride, copper carbonate, copper chloride (II), copper citrate (II), copper formate (II), copper hydroxide (II), copper oleate (II), copper maleate, copper phosphate, sulfuric acid Copper (II), iron acetylacetonate, ferrous ammonium citrate, ferric ammonium oxalate, ferrous ammonium sulfate, ferric ammonium sulfate Water-soluble metal salts such as iron citrate, iron fumarate, iron maleate, ferrous lactate, ferric nitrate, iron pentacarbonyl, ferric phosphate, ferric pyrophosphate; vanadium pentoxide, copper oxide (II), metal oxides such as ferrous oxide and ferric oxide; metal sulfides such as copper (II) sulfide and iron sulfide; and the like.

When polyvalent metal ions are used in the polymerization step, it is preferable to initially charge 80% by mass or more of the total amount of polyvalent metal ions (the metal compound and / or metal) used in 100% by mass into the reaction vessel. is there. More preferably, it is 100 mass%, that is, the whole amount is initially charged.

The amount of the polyvalent metal ion used is 5 to 500 ppm with respect to the total mass of the polymerization reaction liquid when the total amount of the monomer components to be used is added as the amount of the metal compound and / or metal used. Is preferred. If it is 5 ppm or more, there is a tendency that the decomposition efficiency of a polymerization initiator such as persulfuric acid (salt) can be further increased, and if it is 500 ppm or less, the possibility of coloring is more sufficiently suppressed, The effect of addition is more fully expressed.

<Polymerization solvent>
The polymerization step is preferably performed in a solvent. As the solvent, an aqueous solvent is preferably used. The aqueous solvent means water or a mixed solvent of water and an organic solvent. Among the aqueous solvents, an aqueous solvent containing 80% by mass or more of water and 20% by mass or less of an organic solvent is preferable. More preferred is water.
Examples of the organic solvent used for the aqueous solvent include lower alcohols such as methanol, ethanol and isopropyl alcohol; amides such as diethylformaldehyde; ethers such as diethyl ether; The organic solvent can use 1 type (s) or 2 or more types.

In the above polymerization step, the monomer component, the polymerization initiator, the aqueous solvent and other raw materials used as necessary are converted into a theoretical solid content concentration of the copolymer after the completion of polymerization (nonvolatile content in the polymerization solution). It is preferably used in such an amount that it is 40% by mass or more based on 100% by mass of the polymerization solution. Thereby, it becomes possible to narrow the molecular weight distribution of the copolymer.
The theoretical solid content concentration of the copolymer can be adjusted by the mass of each raw material supplied to the reactor by initial charging and dropping. For example, when acrylic acid or (anhydrous) maleic acid and a base such as sodium hydroxide are separately supplied to the reactor and neutralization is performed in the reactor, water may be generated by the neutralization. Must be considered.

<Polymerization temperature>
The temperature during the polymerization reaction (also referred to as polymerization temperature) is preferably 25 to 150 ° C. More preferably, it is 25-99 degreeC. When the temperature is lower than 25 ° C., there is a possibility that an increase in molecular weight or an increase in impurities cannot be sufficiently suppressed, and there is a possibility that the polymerization time is too long and the productivity cannot be further improved. On the other hand, if the polymerization temperature is too high, when using bisulfurous acid (salt) as the initiator system, bisulfurous acid (salt) may be decomposed and a large amount of sulfurous acid gas may be generated. There is a possibility that it cannot be sufficiently prevented that sulfurous acid gas is dissolved and impurities are formed. In addition, the sulfurous acid gas may be discharged outside the system during the polymerization, and there is a possibility that the cost of the recovery process may be increased. In addition, bisulfurous acid (salt) as an initiator system escapes as sulfurous acid gas. As a result, a sufficient effect to meet the requirements cannot be obtained, and the molecular weight tends not to decrease. The lower limit of the polymerization temperature is more preferably 50 ° C. or higher, particularly preferably 70 ° C. or higher. Further, the upper limit of the polymerization temperature is more preferably 95 ° C. or less, and particularly preferably 90 ° C. or less.
Here, “polymerization temperature” means the reaction solution temperature (° C.) in the reaction system.

<Polymerization pressure>
In the polymerization step, the pressure in the reaction system is not particularly limited, and may be any of normal pressure, reduced pressure, and pressurized pressure.

<Method of adding each raw material>
In the polymerization step, a part or all of the monomer component can be added to the reaction vessel (reaction solution) before the polymerization is started, that is, it can be initially charged. In particular, maleic acid (salt) is preferably added to the reaction vessel (reaction solution) in the total amount used before the start of polymerization from the viewpoint of further reducing the residual monomer. It may be added. Moreover, it is preferable that a part or all of acrylic acid (salt) is added to the reaction vessel (reaction solution) after the start of polymerization. By adding a part or all of acrylic acid (salt) after the start of polymerization, the molecular weight distribution of the resulting copolymer can be made narrower, and the calcium scavenging ability and gel resistance of the copolymer composition can be reduced. The sex can be increased. The monomer component may be added alone, or may be added after being dissolved in a solvent such as water or mixed with other raw materials.
In the present specification, “before the start of polymerization” means before the start of polymerization, and “after the start of polymerization” means after the start of polymerization. “Polymerization start time” means the time when part or all of the polymerization initiator and part or all of the monomer component are added to the reaction vessel (reaction liquid).

The polymerization initiator preferably contains persulfuric acid (salt), but the total amount of the polymerization initiator used may be added to the reaction vessel all at once, or a part or all of the polymerization initiator is dropped into the reaction vessel. May be. Preferably, a part or all of the polymerization initiator is dropped into the reaction vessel, whereby the concentration of the polymerization initiator present in the reaction system during the polymerization can be controlled, so that the molecular weight distribution of the polymer is reduced. It can be narrowed. More preferably, 80% by mass or more out of 100% by mass of the total amount of the polymerization initiator used is supplied dropwise to the reaction vessel. More preferably, 100% by mass of the total amount of polymerization initiator used of 100% by mass, that is, the entire amount is supplied dropwise to the reaction vessel.

The addition time (preferably dropping time) of the polymerization initiator to the reaction vessel (reaction solution) is not particularly limited. For example, the polymerization initiator is added until the end of the addition of acrylic acid (salt) or acrylic acid ( The addition is preferably completed within 20 minutes before and after the addition of the salt. More preferably, the addition of the polymerization initiator is completed within 10 minutes before and after the end of the addition of acrylic acid (salt). Thereby, the residual amount of the monomer in the copolymer composition obtained is reduced more.

In the polymerization step, it is preferable that the supply rate (also referred to as polymerization initiator addition rate) of the polymerization initiator (preferably persulfuric acid (salt)) to the reaction vessel is changed at least once during the polymerization. Thereby, since the production | generation of 3-sulfopropionic acid (salt) and 2-sulfosuccinic acid (salt) is suppressed more, these content ratios can be controlled by the range mentioned above, Therefore The copolymer composition obtained Enhances calcium scavenging ability and gel resistance. In this way, the above production method includes a step of adding a part or all of the polymerization initiator to the reaction vessel, and the addition rate of the polymerization initiator is changed at least once during the polymerization. This is one of the preferred forms of the invention.
In addition, when changing the said supply rate at least once during superposition | polymerization, the superposition | polymerization initiator addition speed | rate (for example, average speed within 30 minutes from the time of a superposition | polymerization start time) at the initial stage of superposition | polymerization, A larger (faster) setting is more preferable. That is, a mode in which the addition rate of the polymerization initiator at the initial stage of polymerization is larger than the addition rate of the polymerization initiator in other time zones is one of the preferred modes of the present invention. Thereby, calcium trapping ability and gel resistance can be made more suitable. More preferably, the polymerization initiator addition rate at the initial stage of polymerization (for example, the average rate within 30 minutes from the start of polymerization) is set to a rate 1.1 to 10 times higher than the polymerization initiator addition rate in other time zones. More preferably, the speed is set to 1.2 to 5 times, particularly preferably, the speed is set to 1.25 to 4.5 times, most preferably 1.3 to 5. The speed is set to 4 times.

The above bisulfite (salt) may be added to the reaction vessel (reaction solution) all at once, or a part or all of it may be dropped into the reaction vessel after the start of polymerization. Preferably, part or all of bisulfurous acid (salt) is added to the reaction vessel after the start of polymerization. More preferably, 80% by mass or more of 100% by mass of the total amount of bisulfurous acid (salt) used is supplied dropwise to the reaction vessel, whereby bisulfurous acid (salt) is effectively utilized by the polymerization reaction. The possibility that bisulfite (salt) is decomposed in the initial stage can be sufficiently reduced. More preferably, the total amount used is 100% by mass, ie, 100% by mass, that is, the whole amount is supplied dropwise to the reaction vessel.

The addition time of the bisulfite (salt) to the reaction vessel (reaction solution) is not particularly limited. For example, it is added until the end of the addition of acrylic acid (salt) or the addition of acrylic acid (salt) is completed. The addition is preferably completed within 20 minutes before and after the hour. More preferably, the addition of bisulfite (salt) is terminated within 10 minutes before and after the end of the addition of acrylic acid (salt). Thereby, the calcium capture | acquisition ability and gel resistance of the copolymer composition obtained can be improved more.

In the above polymerization step, when the above-described components and the like are dropped during the polymerization, the dropping time is not particularly limited, but for example, each component is preferably 40 minutes to 420 minutes. More preferably, it is 60 minutes to 360 minutes.
In addition, dripping time may differ with each component. Further, the dropping speed of each component is not particularly limited except for the case mentioned above. For example, the dropping speed may be constant from the start to the end of dropping, and the dropping speed may be changed as necessary.

<Neutralization degree during polymerization>
The polymerization step is also preferably performed under acidic conditions. By carrying out the polymerization reaction under acidic conditions, the increase in the viscosity of the polymerization reaction system solution (preferably an aqueous solution) is sufficiently suppressed, and the low molecular weight copolymer can be produced satisfactorily. In addition, since the polymerization reaction can proceed under a higher concentration condition than in the prior art, the production efficiency can be significantly increased. In addition, since the polymerization reaction can be performed at a high concentration and in one stage by performing the polymerization reaction under acidic conditions, it is possible to omit the concentration step that is necessary in some cases in the conventional manufacturing method. Therefore, the productivity of the copolymer (and the copolymer composition) is further greatly improved, and an increase in production cost can be further suppressed.

In the embodiment in which the polymerization reaction is carried out under the above acidic conditions, the degree of neutralization at the start of polymerization (that is, the degree of neutralization at the time of initial charging) and / or the degree of neutralization at the end of dropping of the monomer components is set to 0 It is preferable to set it to -40%. When the degree of neutralization is within this range, the formation of 3-sulfopropionic acid (salt) and 2-sulfosuccinic acid (salt) is further suppressed, and the content ratio of these in the copolymer composition obtained is described above. Thus, the calcium capturing ability and gel resistance of the resulting copolymer composition can be further improved. The degree of neutralization is more preferably 0 to 35%, further preferably 0 to 33%, and particularly preferably 0 to 30%. From the above viewpoint, it is most preferable to set both the degree of neutralization at the start of polymerization (neutralization at the time of initial charging) and the degree of neutralization at the end of dropping of the monomer component within the above range. It is.
Here, the “polymerization start point” is as described above.
The “neutralization degree” is the ratio (mol%) of salt-type carboxyl groups (neutralized carboxyl groups) to 100 mol% of carboxyl groups in the monomer component contained in the reactor (reaction solution). ). For example, when 1 mol of maleic acid and 1 mol of sodium hydroxide are charged in the reaction liquid contained in the polymerization vessel (reaction vessel) at the start of polymerization, the degree of neutralization at the start of polymerization is 50%. become.
In the polymerization step, it is also preferable to adjust the reaction solution during polymerization so that the pH at 25 ° C. is 1 to 6.

<Manufacturing process other than polymerization process>
In addition to the polymerization process described above, the method for producing the copolymer composition may include one or more other processes. For example, when the copolymer obtained in the polymerization step is an acid type or a partially neutralized type, a neutralization step may be included as necessary. Also, if necessary, a mixing step of adding other components to the copolymer composition produced in the polymerization step; a purification step of removing or reducing a part of the contained components; A dilution step for increasing or decreasing the amount of solvent, a concentration / drying step, and the like may be included.
Thus, in the presence of persulfuric acid (salt) and bisulfurous acid (salt), the process of polymerizing monomer components containing acrylic acid (salt) and maleic acid (salt) is essential, and other processes are optional. The form that may be included is also one of the preferred forms of the present invention.

[Use of copolymer (composition)]
The copolymer composition (and copolymer) of the present invention can be used as, for example, a water treatment agent, a fiber treatment agent, a dispersant, a detergent builder and the like. As a detergent builder, it can be used by adding to detergents for various uses such as clothing, tableware, dwelling, hair, body, toothpaste and automobile. The above-mentioned copolymer composition can be particularly suitably used for water-soluble polymer applications such as such detergent builders. Among these uses, it is preferable to be blended and used in a detergent composition. That is, a detergent composition containing the acrylic acid (salt) -maleic acid (salt) copolymer composition is also one aspect of the present invention. Such a detergent composition can exhibit extremely good calcium scavenging ability and gel resistance by including the above-mentioned acrylic acid (salt) -maleic acid (salt) copolymer. Excellent cleaning ability can be exhibited even in extremely hard water areas such as China and Europe.

The copolymer composition preferably also has a calcium scavenging ability value determined by the method described later of 220 mgCaCO ₃ / g or more. Thereby, it is possible to express even more excellent cleaning ability even in high hardness water. More preferably 230mgCaCO ₃ / g or more, more preferably 240mgCaCO ₃ / g or more, particularly preferably 250mgCaCO ₃ / g or more, and most preferably 260mgCaCO ₃ / g or more.

It is preferable that the copolymer composition further has a degree of gelation obtained by the method described later of less than 0.05. Thereby, even in high hardness water, even more excellent cleaning ability can be expressed, and it can be used more suitably as an additive for detergents. More preferably, it is less than 0.04.

<Detergent composition>
Although the said detergent composition contains the acrylic acid (salt) -maleic acid (salt) type-system copolymer mentioned above, it is suitable that it further contains surfactant. Thereby, more excellent cleaning ability can be exhibited. Surfactant can use 1 type (s) or 2 or more types as needed.
In the detergent composition, the content of the copolymer is preferably 0.1 to 20% by mass with respect to 100% by mass of the total solid content of the detergent composition. More preferably, it is 0.5-15 mass%. Moreover, it is suitable that the content rate of the said surfactant is 5-99.895 mass% with respect to 100 mass% of solid content total amount of a detergent composition. More preferably, it is 5-90 mass%, More preferably, it is 5-70 mass%, Most preferably, it is 20-60 mass%.

As the surfactant, any of an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, and a cationic surfactant can be used.
Examples of the anionic surfactant include alkylbenzene sulfonate, alkyl or alkenyl ether sulfate, alkyl or alkenyl sulfate, α-olefin sulfonate, α-sulfo fatty acid or ester salt, alkane sulfonate, saturated or Examples include unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, amino acid type surfactants, N-acyl amino acid type surfactants, alkyl or alkenyl phosphate esters or salts thereof.
Examples of the nonionic surfactant include polyoxyalkylene alkyl or alkenyl ether, polyoxyethylene alkyl phenyl ether, higher fatty acid alkanolamide or alkylene oxide adduct thereof, sucrose fatty acid ester, alkyl glycoxide, fatty acid glycerin monoester, Examples include alkylamine oxide.
Examples of the amphoteric surfactants include carboxy type or sulfobetaine type amphoteric surfactants.
Examples of the cationic surfactant include quaternary ammonium salts.

If necessary, the detergent composition contains one or more components commonly used in detergent compositions such as enzymes, alkali builders, chelate builders, anti-redeposition agents, fluorescent agents, bleaching agents, and perfumes. You can also

The content of 3-sulfopropionic acid (salt) contained in the detergent composition is 0.0005 to 2% by mass in terms of Na salt type with respect to 100% by mass of the total solid content of the detergent composition. Is preferred. Thereby, it becomes possible to fully exhibit the effect of this invention. The content of 3-sulfopropionic acid (salt) (Na salt type conversion) is preferably 1.9% by mass or less, more preferably 1.8% by mass or less, and still more preferably 1.7% by mass or less. The lower limit of the content of 3-sulfopropionic acid (salt) (in terms of Na salt type) is not particularly limited, but is preferably 0.001% by mass or more, and more preferably 0.01% by mass. That's it.
A detergent composition containing the acrylic acid (salt) -maleic acid (salt) copolymer and a sulfur atom-containing low molecular compound, wherein the sulfur atom-containing low molecular compound is 3-sulfopropionic acid ( And a detergent composition in which the content of the 3-sulfopropionic acid (salt) is 0.0005 to 2% by mass with respect to 100% by mass of the total solid content of the detergent composition. It is one of. Such a detergent composition can be obtained by using the above-described copolymer composition of the present invention.

Since the acrylic acid (salt) -maleic acid (salt) copolymer composition of the present invention has the above-described configuration, both the calcium scavenging ability and the gel resistance are extremely good. It can be suitably used for water-soluble polymer applications such as builders. In addition, the detergent composition including such a copolymer composition and the detergent composition of the present invention exhibit a very good cleaning ability even in extremely hard water areas such as the United States, China and Europe. Can be very useful. Furthermore, if the method for producing an acrylic acid (salt) -maleic acid (salt) copolymer composition of the present invention is used, acrylic acid (salt) -maleic acid excellent in both calcium capturing ability and gel resistance. A (salt) -based copolymer composition can be obtained with high efficiency and ease.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “% by mass”.
In addition, each analysis and measurement was performed by the following method.

<Monomer, 3-sulfopropionic acid disodium (also referred to as “3SPA”) and 2-sulfosuccinic acid trisodium (also referred to as “2SSA”)>
Measurement of the content of monomers and the like was performed using liquid chromatography under the following conditions.
Apparatus: L-7000 series detector manufactured by Hitachi, Ltd .: UV detector L-7400 manufactured by Hitachi, Ltd.
Column: manufactured by Tosoh Corporation ODS-100V 4.6 × 250 mm Two columns Temperature: 20 ° C.
Mobile phase flow rate: 0.5 ml / min
Mobile phase: 5 mmol / L ammonium dihydrogen phosphate (pH 2.4)
Detection wavelength: 210 nm

<Method for quantifying sodium sulfate (Na ₂ SO ₄ )>
The content of sodium sulfate was measured using ion chromatography under the following conditions.
Apparatus: manufactured by Metrohm (762 Interface)
Detector: Made by Metrohm (732 IC Detector)
Ion analysis method: Suppressor method Column: Shodex IC SI-90 4E
Guard column: Shodex SI-90 G
Column temperature: 40 ° C
Eluent: NaHCO ₃ water (2 g diluted to 2000 g with water)
Flow rate: 1.0 mL / min

<Measurement conditions of weight average molecular weight and number average molecular weight (GPC)>
Apparatus: L-7000 series manufactured by Hitachi, Ltd. Detector: RI
Column: SHODEX Asahipak GF-310-HQ, GF-710-HQ, GF-1G 7B manufactured by Showa Denko KK
Column temperature: 40 ° C
Flow rate: 0.5 ml / min
Calibration curve: POLYACRYLIC ACID STANDARD made by Soka Science Co., Ltd.
Eluent: 0.1N sodium acetate aqueous solution

<Measurement of solid content of copolymer composition (copolymer)>
The copolymer composition (1.0 g of the obtained copolymer composition plus 1.0 g of water) was left to dry for 1 hour in an oven heated to 170 ° C. in a nitrogen atmosphere. From the mass change before and after drying, the solid content (%) and the volatile component (%) were calculated.

<Evaluation of calcium capturing ability (also called Ca capturing ability)>
In a beaker having a capacity of 100 cc, 50 g of a 0.001 mol / L calcium chloride aqueous solution was sampled, and 10 mg of the copolymer composition was added in terms of solid content. Next, the pH of this aqueous solution was adjusted to 9-11 with dilute sodium hydroxide. Then, 1 ml of 4 mol / L potassium chloride aqueous solution was added as a calcium ion electrode stabilizer under stirring.
Free calcium ion was measured using an ion analyzer (EA920 type, manufactured by Orion) and a calcium ion electrode (93-20 type, manufactured by Orion). Whether calcium ions were chelated (calcium capturing ability, which is one type of chelating ability) was calculated. The unit of calcium scavenging ability is “mgCaCO ₃ / g”.

<Evaluation of gel resistance>
To a 500 mL conical beaker, pure water, boric acid-sodium borate pH buffer solution, copolymer composition and calcium chloride solution are added in order, and the copolymer composition is added at a solid content concentration of 100 mg / L. In addition, after preparing each test solution with a calcium concentration of 50 mg CaCO ₃ / L and a pH of 8.5, it was sealed with a polyvinylidene chloride film and allowed to stand in a constant temperature bath at 90 ° C. for 1 hour. The gel resistance was evaluated.
When precipitation occurs, it can be said that the gel resistance is extremely low.
In the case where precipitation did not occur, the mixture was stirred and then placed in a quartz cell having an optical path length of 5 cm, and the absorbance (a) at a UV wavelength of 380 nm was measured. As a blank, a test solution obtained by removing the calcium chloride solution from the aqueous solution as the test solution was prepared, and the absorbance (b) was measured by performing the same operation, and the gelation degree was determined from the following equation.
Gelation degree = (a) − (b)
It can be said that the smaller the numerical value of the degree of gelation, the higher the gel resistance.

Example 1
A 2.5 L SUS separable flask equipped with a reflux condenser and a stirrer was charged with 180.8 g of ion-exchanged water and 49.0 g of maleic anhydride (hereinafter also referred to as “anhydrous MA”), and further with 48% water. 25.0 g of an aqueous sodium oxide solution (hereinafter also referred to as “48% NaOHaq”) was added. Then, it heated up to 85 degreeC under stirring. After the internal temperature reaches 85 ° C., the temperature is maintained at 85 ° C., and 405.0 g of 80% acrylic acid aqueous solution (hereinafter also referred to as “80% AAaq”), 112.5 g of 48% NaOH aqueous solution, 35% sodium bisulfite aqueous solution ( Hereinafter, 157.1 g of “35% SBSaq” and 100.0 g of 15% sodium persulfate aqueous solution (hereinafter also referred to as “15% NaPSaq”) were added to each 80% acrylic acid for 180 minutes from separate dropping nozzles. The 48% aqueous sodium hydroxide solution was added dropwise over 180 minutes and the 35% aqueous sodium bisulfite solution was added dropwise over 170 minutes. The 15% aqueous solution of sodium persulfate was dropped in an amount of 1.3 g per mole of acid (total amount of acrylic acid and maleic anhydride) for the initial 30 minutes, and the acid was added for 30 to 190 minutes. An amount of 1.7 g per mole was added dropwise.
After completion of the dropwise addition, the reaction solution was kept at 85 ° C. for 30 minutes for further aging. After completion of the polymerization, the reaction solution was cooled, and neutralized by gradually dropping 275.0 g of 48% aqueous sodium hydroxide solution. In this way, an acrylic acid (salt) -maleic acid (salt) copolymer composition having a solid content concentration of 47.5% and a final neutralization degree of 90% was obtained. Each physical property of the obtained copolymer composition was measured, and the results are summarized in Table 3.

Example 2
A 2.5 L SUS separable flask equipped with a reflux condenser and a stirrer was charged with 180.8 g of ion-exchanged water and 49.0 g of maleic anhydride, and further 25.0 g of 48% aqueous sodium hydroxide was added. . Then, it heated up to 85 degreeC under stirring. After the internal temperature reaches 85 ° C., the temperature is maintained at 85 ° C., 80% acrylic acid aqueous solution 405.0 g, 48% NaOH aqueous solution 112.5 g, 35% sodium bisulfite aqueous solution 157.1 g, and 15% sodium persulfate. 100.0 g of the aqueous solution was dropped from separate dropping nozzles over 80 minutes for 80% acrylic acid, 180 minutes for 48% aqueous sodium hydroxide, and 170 minutes for 35% aqueous sodium bisulfite. In addition, 15% sodium persulfate aqueous solution was dropped in an amount of 1.3 g per mole of acid (total amount of acrylic acid and maleic anhydride) for the initial 30 minutes, and for 30 to 60 minutes, acid was added. An amount of 0.7 per mol was added dropwise, and an amount of 1.0 g per mol of acid was added dropwise for 60 to 190 minutes.
After completion of the dropwise addition, the reaction solution was kept at 85 ° C. for 30 minutes for further aging. After completion of the polymerization, the reaction solution was cooled, and neutralized by gradually dropping 275.0 g of 48% aqueous sodium hydroxide solution. Thus, an acrylic acid (salt) -maleic acid (salt) copolymer composition having a solid content concentration of 47.9% and a final neutralization degree of 90% was obtained. Each physical property of the obtained copolymer composition was measured, and the results are summarized in Table 3.

Examples 3-11
The same procedure as in Example 2 was performed except that the initial charge amount, the dripping amount, and the post-neutralization amount as shown in Table 1 were used. The physical property measurement results of the obtained copolymer composition are summarized in Table 3.

Comparative Example 1
A 2.5 L SUS separable flask equipped with a reflux condenser and a stirrer was charged with 180.8 g of ion-exchanged water and 49.0 g of maleic anhydride, and further 50.0 g of 48% aqueous sodium hydroxide was added. . Then, it heated up to 85 degreeC under stirring. After the internal temperature reaches 85 ° C., the temperature is maintained at 85 ° C., 80% acrylic acid aqueous solution 405.0 g, 48% NaOH aqueous solution 87.5 g, 35% sodium bisulfite aqueous solution 157.1 g, and 15% sodium persulfate. 100.0 g of aqueous solution from separate drop nozzles, 80% acrylic acid for 180 minutes, 48% sodium hydroxide aqueous solution for 180 minutes, 35% sodium bisulfite aqueous solution for 170 minutes, 15% sodium persulfate aqueous solution for 190 minutes It was dripped over.
After completion of the dropwise addition, the reaction solution was kept at 85 ° C. for 30 minutes for further aging. After completion of the polymerization, the reaction solution was cooled, and neutralized by gradually dropping 275.0 g of 48% aqueous sodium hydroxide solution. In this way, an acrylic acid (salt) -maleic acid (salt) copolymer composition having a solid content concentration of 47.5% and a final neutralization degree of 90% was obtained. Each physical property of the obtained copolymer composition was measured, and the results are summarized in Table 3.

Comparative Examples 2-3
The same procedure as in Comparative Example 1 was performed except that the initial charge amount, the dripping amount, and the post-neutralization amount as shown in Table 2 were used. The physical property measurement results of the obtained copolymer composition are summarized in Table 3.

Comparative Example 4
A 2.5 L SUS separable flask equipped with a reflux condenser and a stirrer was charged with 111.4 g of ion-exchanged water and 64.7 g of maleic anhydride, and further added with 101.3 g of 48% aqueous sodium hydroxide. . Then, it heated up to 85 degreeC under stirring. After the internal temperature reaches 85 ° C., the temperature is maintained at 85 ° C., and the 80% acrylic acid aqueous solution 365.6 g, 48% NaOH aqueous solution 311.4 g, 35% hydrogen peroxide aqueous solution 80.9 g, and 15% sodium persulfate 157.3 g of aqueous solution from separate drop nozzles, 80% acrylic acid for 300 minutes, 48% sodium hydroxide aqueous solution for 300 minutes, 35% hydrogen peroxide aqueous solution for 300 minutes, 15% sodium persulfate aqueous solution for 320 minutes Dripped over.
After completion of the dropwise addition, the reaction solution was aged for another 30 minutes while maintaining the reaction solution at 85 ° C., and then cooled to obtain acrylic acid (salt) having a solid content concentration of 41.0% and a final neutralization degree of 92.2%. A maleic acid (salt) copolymer composition was obtained. Each physical property of the obtained copolymer composition was measured, and the results are summarized in Table 3.

In Tables 1 and 2, “aq” means an aqueous solution. Further, “15% NaPSaq constant” means that the dropping rate of the 15% NaPS aqueous solution is kept constant without being changed halfway.

From Table 3, the acrylic acid (salt) -maleic acid (salt) copolymer composition of the present invention has a high calcium scavenging ability of 270 mgCaCO ₃ / g or more and a gelation degree of 0.04 or less. It was found to be low and very excellent in gel resistance. On the other hand, when the content of 3-sulfopropionic acid (salt) is greater than the amount specified in the present invention or when it is not contained at all, it has been found that the gel resistance is particularly poor. Further, during the production of the copolymer composition, a part or all of persulfuric acid (salt) as a polymerization initiator is added to the reaction vessel, and the addition rate of the polymerization initiator is changed at least once during the polymerization. Thus, it was found that the acrylic acid (salt) -maleic acid (salt) copolymer composition of the present invention having a high calcium capturing ability and excellent gel resistance can be preferably obtained. In particular, by increasing the addition rate of the polymerization initiator for 30 minutes from the start of the polymerization to be higher than the addition rate of the polymerization initiator in other time zones, the calcium trapping ability and the gel resistance are improved. I understood that.

Claims (4)

A copolymer composition comprising an acrylic acid (salt) -maleic acid (salt) copolymer and a sulfur atom-containing low molecular weight compound,
The copolymer includes a structural unit (I) represented by the following general formula (1) and a structural unit (II) represented by the following general formula (2):
The content molar ratio of the structural unit (I) to the structural unit (II) (structural unit (I) / structural unit (II)) is 80/20 to 95/5,
The weight average molecular weight of the copolymer is 2000 or more and 10,000 or less,
The sulfur atom-containing low molecular weight compound includes 3-sulfopropionic acid (salt),
The content of the 3-sulfopropionic acid (salt) based on the total solid content 100 wt% of the copolymer composition, I 0.01-10% by mass,
The copolymer composition includes a step of polymerizing a monomer component containing acrylic acid (salt) and maleic acid (salt) in the presence of persulfuric acid (salt) and bisulfite (salt). acrylic acid (salt), characterized by being obtained by - maleic acid (salt) copolymer composition.

In formula (1), M represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group.

In formula (2), M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group or an organic amine group. A method for producing the acrylic acid (salt) -maleic acid (salt) copolymer composition according to claim 1,
The production method includes a step of polymerizing a monomer component containing acrylic acid (salt) and maleic acid (salt) in the presence of persulfuric acid (salt) and bisulfurous acid (salt). A method for producing an acrylic acid (salt) -maleic acid (salt) copolymer composition. A detergent composition comprising the acrylic acid (salt) -maleic acid (salt) copolymer composition according to claim 1. A detergent composition comprising an acrylic acid (salt) -maleic acid (salt) copolymer and a sulfur atom-containing low molecular weight compound,
The copolymer includes a structural unit (I) represented by the following general formula (1) and a structural unit (II) represented by the following general formula (2):
The content molar ratio of the structural unit (I) to the structural unit (II) (structural unit (I) / structural unit (II)) is 80/20 to 95/5,
The weight average molecular weight of the copolymer is 2000 or more and 10,000 or less,
The sulfur atom-containing low molecular weight compound includes 3-sulfopropionic acid (salt),
The content of the 3-sulfopropionic acid (salt) based on the total solid content 100 wt% of the detergent composition, I 0.0005% by mass,
The detergent composition is obtained by a production method including a step of polymerizing a monomer component containing acrylic acid (salt) and maleic acid (salt) in the presence of persulfuric acid (salt) and bisulfite (salt). A detergent composition characterized by that.

In formula (1), M represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group.

In formula (2), M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group or an organic amine group.